Study of the Pollen Grain Metabolome under Deposition of Nitrogen and Phosphorus in Taxus baccata L. and Juniperus communis L.

Nitrogen plays an important role in both quantitative and qualitative aspects of plant reproduction, including pollen grain compounds and seed production. Recent studies have pointed out that pollen grains produced by male plants of T. baccata and J. communis subjected to a long period of fertilizer supplementation have lower in vitro germination ability and higher nitrogen content. To gain molecular insights into these observations, we conducted GC-MS analysis of both species to characterize the metabolomes of dry, mature pollen grains, which allowed for the identification and quantification of more than 200 metabolites. The results demonstrated that fertilizer supplementation impacts the relative content of 14 metabolites in J. communis (9 downregulated and 5 upregulated) and 21 in T. baccata (6 downregulated and 15 upregulated). Although plants showed little similarity in patterns, in metabolite profiles, both up and down fold-changes were observed. This is the first report on the gymnosperm pollen grain metabolomic profile and changes induced by long-term nitrogen and phosphorus supplementation. Pollen grains produced by fertilizer-supplemented male individuals had significantly lower relative content of linolenic acid, 5,6-dihydrouracil, maltotriose, galactonic acid, D-xylulose, and glycerol-α-phosphate but higher content of sorbitol, glucosamine, and 1,5-anhydro-D-glucitol as well as n-acetyl-d-hexosamine, dimethyl phthalate, glycine, galactose-6-phosphate, D-fructose-6-phosphate, pyroglutamic acid, and 3-(3-hydroxyphenyl)-3-hydroxypropionic acid. Thus, in pollen grain samples earlier shown to have different germination abilities, the presence of different metabolites indicates a significant environmental impact on the quality of gymnosperm pollen grains.

The higher availability of nutrients increases the production but decreases the quality of pollen grains in Juniperus communis L.

Next to global warming, excessive deposition of nitrogen has an alarming environmental impact on forest ecology, especially within dioecious species. Resource availability affects seed quality and can affect the distribution of plant species. Lower seed productivity can also be a result of limited pollen availability or lower pollen quality. A few studies have assessed the effect of nutrient availability on the quantity and quality of pollen grains produced. Therefore, rooted shoots of dioecious, male Juniperus communis L. grown in different nutritional conditions were used to assess the impact on productivity and quality attributes of produced pollen grains (pollen volume, morphology, germination, and chemical composition). The results indicated that nutrient availability impacts pollen grain development. Male plants growing in nutrient-rich environments appear to compensate for the lower quality of produced pollen grains by producing a higher number of male cones and thus a greater quantity of pollen. In contrast, the opposite was observed in plants growing in nutrient-poor environments. The availability of nitrogen and other nutrients will probably continue to impact soils in the foreseeable future due to anthropogenic activity and can be one of the drivers that can impact the reproduction and distribution of plants.

Camelina sativa cake improved unsaturated fatty acids in ewe's milk.

BACKGROUND: Camelina sativa cake (CSC), a rich source of unsaturated fatty acids, in the case of ruminants, may improve the energy value of a diet and also increase the unsaturated fatty acid content in milk. Effects of basal diet (control), basal diet plus 30 g kg(-1) of CSC in dietary dry matter (DM), basal diet plus 60 g kg(-1) of CSC in dietary dry matter on milk production and the fatty acid composition of ewe's milk with particular emphasis on the monoenes and conjugated isomers of linoleic acid content were examined. RESULTS: Elevated concentration of total monounsaturated fatty acids, the effect of an increase in monounsaturated fatty acids in the trans configuration, as well as the increased content of total polyunsaturated fatty acids, resulted from CSC supplementation. Total saturated fatty acid concentration was decreased. CONCLUSION: Milk from CSC-supplemented ewes was characterized by increased levels of beneficial nutritional factors, including mono- and n-3 polyunsaturated fatty acids, and was also by lower atherogenic and thrombogenic indices. Taking into consideration all the obtained results and recommended fat concentrations in a daily ruminant ration, we recommend supplementing a dairy ewe's diet with 30 g kg(-1) DM of CSC cake in practice.